Knurling tool



H. BOYAR KNURLING TOOL Filed Jan. 24, 1945 C QTTOQ E SZ 0 m p 3 M W 1 W; 46 a.

Patented Mar. 2, .1948

KNURLING TOOL Harry Boyar, Oak Park, 111., assignor to Boyar- Schultz Corporation, Chicago, Ill, a corporation of Illinois Application January 24, 1945, Serial No. 574,394

10 Claims. 1

The invention relates to improvements in knurling tools generally and more particularly to knurling tools of the swing type adapted for use in automatic screw machines and similar machine tools.

One object of' the invention is to provide a knurling tool of the above general character adapted to perform a knurling operation without subjecting the Work or the work supporting structure to objectionable transverse strains.

A more specific object is to provide a knurling tool equipped with a plurality of knurls and so constructed and arranged that the knurls may be applied simultaneously to opposite sides of the work.

Another object is to provide improved means for equalizing the feed of the knurls and the pressure exerted on the work thereby.

Another object is to provide new and improved means for knurling behind shoulders or larger diameters on workpieces, in that the tool is designed to open over shoulders and close behind shoulders without need for manual adjustment.

A further object is to provide a double knurling tool which automatically adapts itself for operating on workpieces of different diameters.

Other objects and advantages of the invention will become apparent from the following detailed description of the preferred embodiment illustrated in the accompanying drawing in which:

Figure 1 is a perspective view of a knurling tool embodying the features of the invention.

Fig. 2 is an end view of the tool with the front cover plate removed.

Fig. 3 is a side elevational view of the tool with parts broken away to show details of construc tion.

Fig. 4 is a sectional view of the tool taken in a vertical plane substantially on the line 44 of Fig. 3.

While the invention is susceptible of various modifications and alternative constructions, I have shown in the drawings and will herein describe in detail the preferred embodiment, but it is to be understood that I do not thereby intend to limit the invention to the specific form disclosed, but intend to cover all modifications and alternative constructions falling within the spirit and scope of the invention as expressed in the appended claims.

For purposes of illustration, the improved knurling tool has beenshown in the form best suited for use in an automatic screw machine of the well known type having a: tool support" or turret 5 (Fig. 1) indexible about a horizontal axis to present difierent tools to the work and translatable on ways 6 toward andfrom a rotatably supported workpiece W carried in a suitable collet (not shown). The turret is constructed to index the tool into a position of axial alinement with the workpiece, and turret translation carries the tool into and out of working position'with reference to the work. Suitable means, such as the usual guide or plate I, which may be either fixed or adjustable, is provided for actuating the tool to feed the knurls against the sides of the workpiece in response to the forward movement of a cross slide (not shown) carrying the guide.

In carrying out the invention, the improved knurling tool is constructed with a pair of elongated knurled supporting elements or levers Ill and H each pivoted at one end On a rigid body l2 adapted to be mounted in the turret 5. The levers l0 and H are spaced apart to straddle the workpiece W and are interconnected in a novel manner for conjoint swinging movement whereby conventional revoluble knurls l3 and HI carried by the respective levers are fed simultaneously against opposite sides of the workpiece with substantially equal pressures. The equalization of the pressures exerted by the opposed knurls is obtained through equalization of the feed movements and is advantageous in completely eliminating lateral strains on the workpiece and the work support. Horizontal springing or bending of the workpiece in the illustrated tool is thus avoided, making the application of knurling possible in some instances where it otherwise simply could not be used, and in other instances rendering the quality of the work performed materially superior to that available from previous knurling tools.

The tool body I2, in its preferred form, comprises an elongated supporting element or shank l6 adapted to be received in the usual tool socket provided in the turret 5 and having a rigid face plate H at one end. As herein shown, the face plate is generally triangular in shape and is formed integral with the shank It. The latter is preferably of hollow construction to permit a workpiece to project therein when the knurling operation is to be performed at a point spaced substantially from the end of the piece.

To provide for recentering the knurls l3 and M with respect to workpieces, which is necessary to compensate for misalinement between turret and work, the knurl supporting levers It! and H are carried by an adjustable mounting plate 20. The mounting plate is secured to the face plate I! by suitable screws 2! projecting through apertures 22 in the face plate and threading into the mounting plate. The lower one of the apertures 22 is dimensioned to provide clearance for the body of the screw passing through it so that the mounting plate may be moved or pivoted laterally'about the upper one of the screws 2| to selected positions of adjustment. By tightening the lower screw 2|, the mounting plate may be locked securely in adjusted posi-- tion.

As will be seen by reference to the drawing,

the levers l0 and II are arranged in side-b'y-side relation and are confined between the mounting plate and a cover plate 23. The two plates and the upper ends of the respective levers are provided with alined holes for the re- 25 threaded on the inner ends of the pivot pins maintain the parts in assembled relation.

To insure firm support for the knurls l3 and I4, each of the levers l0 and H is formed with a rigid, forwardly projecting arm or bracket 26 adapted to support one end of a shaft 21 upon which the knurl is rotatably supported. The other end of the shaft may be supported in a recess in the associated lever, the brackets and recesses being located so that the rotational axes of the knurls are parallel to the axis of the workpiece.

In order to produce a cleanly knurled surface on the workpiece and to avoid imposing objectionable strains thereon, provision is made for feeding the opposed knurls l3 and 14 into the work to exactly the same depth and with substantially equal pressures. To this end, the knurl supporting levers l0 and H are formed with interengaging shoulder elements 39 and 3| constructed and arranged so that the pivotal movements of one lever are transmitted to the companion lever to produce an equal, but oppositely directed movement of the same. As shown in Fig. 2, the shoulder element 30 is formed adjacent to the pivoted end of the lever l0 and is arranged to project laterally from the inner side thereof while the shoulder element 3| is similarly formed on the'lever II to project laterally from the inner side to overlie the element 30.

Accurate egagement of the shoulders is maintained in all positions of the levers by forming the shoulder elements with arcuate contact surfaces 32 and 33 located so that the line of contact always lies in a common plane with the pivotal axes of the levers It! and H. With this construction, any slight wear incident to long continued use of the tool is distributed uniformly over both contact surfaces and therefore does not affect the accuracy of the movements transmitted thereby. The contact surfaces are hardened to minimize wear.

Actuation of the levers l0 and II to feed the knurls to the work is effected by the guide I through coaction with one of the levers. In the particular tool illustrated, the lever I0 is made substantially longer than the lever H and carries at its lower or free end a guide-engaging element, herein shown as a cap screw 35 threaded into the lever. The screw 35 is positioned to be engaged by the guide I in the forward movement of the cross slide carrying the latter. The extent of movement of the levers by the cam bar may be regulated by appropriate setting of the adjusting screw 35 which is then looked in place by means of a lock nut 36 threaded thereon.

-Means is provided for yieldably urging the knurl supporting levers I ii and II to a re- 'tra'cted" or inactive position to facilitate entry and exit of the work from the space between the knurls. This means, as shown in Fig. 4, comprises a compression spring 4|] confined between a pair'of plungers 4| slidable in a recess 42 extending transversely through the mounting plate 20. The plungers are positioned to bear against pins 43 rigid with and projecting rearwardly from the levers I0 and II. The limit position of the levers is determined by a pin 44 rigid with the lever l0 and projecting rearwardly therefrom into an opening 45 in the plate 20 for engagement with an adjustable stop screw 46 threaded into the plate.

In operation, the tool is secured in the turret of the machine substantially in alinement with a workpiece held in the rotating spindle collet or work support of the-machine. In setting up the tool some adjustment may be requisite to take care of misalinement in the machine between turret and collet so that the work will be precisely alined with the tool. This adjustment is effected by loosening the screwsZl and utilizing the clearance in the lower one of the apertures 22 to shift the mounting plate 20 and assembled lever mechanism to bring the knurls into proper relation to the work. When the adjustment is made, the parts are secured inadjusted position by tightening the screws 2|. The depth of feed of the knurls may be regulated through the medium of the adjusting screw 35, this setting remaining fixed for work of the same class.

As the cross slide moves forwardly, the adjusting screw 35 engages the guide 1, thus swinging the lever in inwardly. A corresponding swinging movement is imparted to the lever II through the interengaging contact surfaces 32 and 33 of the elements 30 and 3|. The levers Ill and II are thus rocked through precisely the same arc, and, since the knurls carried by the levers were initially centered with respect to the work, they are thus fed into the work to equal depths and with substantially equal pressures. As the knurls are disposed on opposite sides of the work, the pressures exerted thereby are balanced and substantially no transverse strains are imposed on the Work. Objectionable springing of the work, such as occurs with conventional single knurl swing tools, is thus avoided and a clean accurate knurled surface is produced on the work.

It will be apparent from the foregoing that the invention provides a knurling tool of novel and advantageous construction particularly suitable for use in automatic screw machines and the like. Through the provision of opposed knurls adapted to be fed simultaneously against opposite sides of the work to equal depths and with equal pressure, the knurling operation may be performed without subjecting the work or its supporting structure to objectionable transverse strains. Due to the novel manner in which the antenna are slmported, adjustments: may be read;- ily made to. adapt the tool for operating on workspieces: of difierent diameters, The improved tool is simple and mggedm construction and so designed their the. normal wear incident to con-- tinued use does not affect its accuracy.

I claim as: my invention:

1.. A knurling tool comprising, in combination, a supporting element, a pair of levers pivotally mounted on said element in. laterally spaced relation and adapted to carry revoluble knurls po sitioned to engage opposite sides of. a workpiece, means for rocking one of said levers about its pivot to. feed the knurl carried thereby to the workpiece, and means on said one lever coastin with means on the other lever for simultaneously rocking said other lever by movement of the first lever to feed the knurl carried thereby to the workpiece, said coacting means acting to equalize the pressure exerted by said knurls on the workpiece.

2. In a knurling tool, in combination, a rigid body, a pair of knurl supporting elements mounted on said body and spaced apart to receive a workpiece therebetween, said supports being movable toward and from the workpiece, means for shifting one of said elements toward the workpiece, and means on said one element coacting with means on the other element upon shifting of the first element for correspondingly shifting said other element.

3. A knurling tool comprising, in combination, a supporting element, a pair of levers pivotally mounted on said element in laterally spaced relation, said levers being adapted to carry revoluble knurls positioned to engage opposite sides of a workpiece, and shoulder elements formed on adjacent sides of the respective levers and projecting laterally therefrom into overlying relationship, said. shoulder elements having contact surfaces adapted to coact in the pivotal movement of the levers to maintain such movements substantially equal.

4. In a knurling tool, the combination with a rigid body supported for relative movement axially of a rotatably supported workpiece, a pair of supporting elements mounted on said body for movement toward and from each other and spaced apart to receive the workpiece therebetween, said elements being shaped to carry revoluble knurls disposed with their axes parallel to the axis of the workpiece, means operable in response to a relative movement of the tool body with respect to the workpiece for shifting one of said supporting elements toward the workpiece, and means on said one element coacting with means on the other element for correspondingly shifting the latter element, said coacting means being operative to equalize the movements imparted to said elements.

5. A knurling tool comprising, in combination, a supporting element, a pair of levers pivotally mounted on said element in laterally spaced relation and adapted to carry revoluble knurls positioned to engage opposite sides of a workpiece, a shoulder element projecting laterally from one lever toward the other lever, a shoulder element projecting laterally from said other lever to overlie said first mentioned shoulder element, said shoulder elements acting to transmit the pivotal movement of said one lever to said other lever and thereby equalize the pressure exerted by the knurls on the workpiece.

6. A knurling tool comprising, in combination, a supporting element, a pair of levers pivotally mounted on saidv element in laterally spaced relation and adapted to carry revoluble knurls. p.0- sitioned' to engage opposite: sides or a workpiece, interengaging contact surfaces on said levers. operative to transmit the pivotal movements of one lever to the other lever, and an extension on said one lever for rocking the lever about its pivot.

7'. A knurling tool having a supporting element adapted to be mounted adjacent one end of a rotatably driven workpiece for movement axially thereof, a pair of levers supported in side-byside relation on said element to rock about axes substantially parallel to the rotational axis of the workpiece, the axes of said levers being oflset laterally with respect to the axis of the workpiece whereby the levers are adapted to straddle the workpiece, knurls carried by said levers on opposite sides of the workpiece, spring means yieldably urging said levers outwardly to permit entry and exit of the workpiece between said knurls, and means for simultaneously rocking said levers inwardly to feed the knurls against opposite sides of the workpiece, said last mentioned means being operative to equalize the pressure exerted by the knurls on the work and thereby avoid imposing transverse strains there- 8. A knurling tool having a supporting element adapted to be mounted adjacent one end of a rotatably driven workpiece for movement axially thereof, a pair of levers supported in sideby-side relation on said element to rock about axes substantially parallel to the rotational axis of the workpiece, the axes of said levers being offset laterally with respect to the axis of the workpiece whereby the levers are adapted to straddle the workpiece, knurls carried by said levers on opposite sides of the workpiece, spring means yiel dably urging said levers outwardly to permit entry and exit of the workpiece between' said knurls, means rigid with one of said levers engageable by a cam or the like in the movement of the supporting element for rocking said one lever in a direction effective to feed the knurl carried thereby against one side of the workpiece, and motion transmitting means interposed between said levers operative in response to the rocking of said one lever to correspondingly rock the other of said levers and thereby feed the knurl carried thereby against the opposite side of the workpiece.

9. A knurling tool having a supporting element adapted to be mounted adjacent one end of a rotatably driven workpiece for movement axially thereof, a pair of levers supported in side-by-side relation on said element to rock about axes substantially parallel to the rotational axis of the workpiece, the axes of said levers being offset laterally with respect to the axis of the workpiece whereby the levers are adapted to straddle the'workpiece, knurls carried by said levers on opposite sides of the workpiece, spring means yieldably urging said levers outwardly to permit entry and exit of the workpiece between said knurls, adjustable means for limiting the outward movement of said levers, an extension on one of said levers adapted to coact with a cam or the like in the movement of said supporting eleknurls against the piece.

10. A knurling tool comprising, in combination, an elongated supporting element having a rigid face plate at one end, a mounting plate abutting. said face plate for relative face to face movement laterally of said element, a pair of levers pivotally supported on said mounting plate in laterally spaced relation and adapted to carry revoluble' knurls positioned to engage opposite sides of the workpiece, means for rocking said levers in a direction to feed the knurls simultaneously to the work, and means for clamping said mounting plate and said face plate together, said opposite side of the workclamping means including structure for permit- 5 2,294,685

8 ting, prior to clamping, a limited adjusting movement of the mounting plate on said face plate substantially along a line connecting the knurl axes for simultaneously moving both of the knurls to position them equidistant from the work axis.

,- HARRY BOYAR.

REFERENCES CITED UNITED STATES PATENTS Name Date Nelson Sept. 1, 1942 Number 

